The present invention relates to devices for correcting colour information supplied by a camera of a video transmission system with a view to obtaining, on reception, a picture containing the maximum of visible information.
In black and white picture transmission systems, a correction device for improving the perception of pictures is already known (U.S. Pat. No. 4,337,514 filed by the Applicant Company). The process performed by this device consists of correcting the luminance signal supplied by the camera or pickup tube of a black and white camera by means of a non-linear quadripole with variable characteristics and controlled in such a way that the histogram of the values of the corrected luminance signal has a flat form whatever the shooting conditions, which corresponds to a regular distribution of the values on the scale of said values. In its present form, this correction device does not make it possible to improve colour pictures, it only being usable in connection with the improvement of the black and white pictures.